1. Field of the Invention
The invention relates to apparatus, systems, and methods for pressure relief through an orifice and, more particularly, to an umbrella type check valve.
2. Background of the Invention
There are many applications where it is desirable to provide a pressure relief at a particular location. For example, an automotive application may utilize a crankcase breather valve for ventilation and pressure control in an internal combustion engine while also controlling the direction of flow of fluids, pressure, contaminants, etc. Other examples of pressure relief and flow control may be found in automotive as well as medical, appliance, manufacturing process, pumps, and other areas of technology.
An umbrella type check valve is known. Typically, such a valve has a spherical surface that substantially conforms to the contour of the underside of the check valve. The valve is formed of an elastic material so that the spherical surface returns to its nominal shape after being temporarily deformed. The spherical ‘cap’ is typically formed along with a plug or stem that is inserted into an orifice for securing the cap in a position that ‘seats’ against a mounting surface. When the pressure adjacent the orifice becomes large enough, the pressure passes to the underside of the cap and causes the cap to lift off the mounting surface, thereby releasing the pressure to the outside. After releasing the pressure, the elastic cap returns to its seated position on the mounting surface.
However, such umbrella check valves require that holes be drilled or otherwise machined in a plug portion of the valve or in the adjacent mounting surface, in order to provide a pathway for passing the pressure from beneath the plug to the underside of the cap. This machining is expensive, resulting in a higher cost and longer manufacturing time for the umbrella valve. In addition, the extra holes in the plug or mounting surface may result in impurities entering the holes thereby defeating a one-way function of the umbrella valve. Additional related problems exist for conventional umbrella valves.